How to add the neighboring pixel values

I have a matrix - if 0 occurs then i have to add the 8 neighboring pixels and replace the 0 value . is there any built in function for this ..

Answer 1

[Walter Roberson]

filt2() with [1 1 1;1 0 1; 1 1 1] to get the sums everywhere. Then in the places that are 0 in the original, replace with the sum at the corresponding location. Use logical indexing.